The ECHO 1 Modular Tactical Carbine 1 features M4 magazine well for more universal use of M4 magazines, a 6-position crane stock, ambidextrous fire selector, and integrated RIS system for mounting flashlights, lasers, vertical grips, or any other accessories. The gun also features a full-length top rail, with built-in front and rear sights, for adding your favorite of optics.